Some systems for removing moisture from the inlet stream of gas turbines are known. One such known system includes a plurality of filtering mechanisms that filter the inlet air through a plurality of materials and mediums before the inlet air is allowed to proceed to the gas turbine. In one such system, the plurality of filters can include a preliminary filter suspended or attached to the weather hood or hood which is upstream from a primary filter. The filter system is connected by ducting to the gas turbine. The preliminary filters are constructed from filter media that may have hydrophobic properties, for example, a polypropylene fiber material. Filtering mechanisms serve a primary function to filter solid particulates, but typically fail to control moisture.
Fine moisture droplet contamination is particularly problematic in environments having relatively high humidity, such as in marine or off-shore applications, or in conditions such as rain, mist or fog. Where such fine droplets occur, they can migrate through the filter media. This type of fine moisture droplet migration can cause substantial problems with gas turbine operations. It is well known that light rain, mist, and fog create very small moisture droplets or fine water particles that are easily carried in a fast moving stream of air, such as inlet air for a gas turbine. Generally, heavy rain has drops that are too large to be easily carried in a flow of inlet air.
Attempts to collect fine water particles generally in the range of approximately 0.01 micron to approximately 40 microns have been unsuccessful. For example, some filtration systems using filter media experience increased pressure loss across a filter due to the moisture, which results in reduced gas turbine performance during this period of “wet” operation. This is especially true for cellulose fiber filters which swell when they are wet. Some filter media also retain the moisture which can lead to long periods of time when the pressure loss across the filter is elevated.
A mist eliminator, a moisture removal system employing the mist eliminator, and a method of removing water particles from inlet air that do not suffer from the above drawbacks are desirable in the art.